The susceptibility of magnesium at 300 K is 1.2×10−5. The temp is 800× t K, the susceptibility is 1.8×10−5. Then the value of 't' is
As per Curie's Law , χ=CT ⇒χ1χ2=T2T1
⇒T2=T1χ1χ2 ⇒T2=3001.2×10−51.8×10−5
⇒T2=300×1218 ⇒T2=800×t.K=200K
⇒t=14=0.25